Interneurons transmit C fiber impulses to lamina V from which laminae?

Interneurons transmit C fiber impulses to lamina V from which laminae?

• A. Lamina I and II
• B. Lamina II
• C. Lamina III
• D. Lamina II and III

Answer: (D)

The key idea is how nociceptive signals from C fibers are relayed through the dorsal horn to higher centers. C fibers enter the dorsal horn and connect with interneurons in the substantia gelatinosa (lamina II) and also in lamina III. These interneurons then relay the signal to lamina V, where wide dynamic range neurons integrate input from various fibers and send projection signals up the spinothalamic pathway. While C fibers also connect to lamina I, the interneuron-mediated relay to lamina V most consistently involves lamina II and III, making those layers the source of the C-fiber input to lamina V.

The key idea is how nociceptive signals from C fibers are relayed through the dorsal horn to higher centers. C fibers enter the dorsal horn and connect with interneurons in the substantia gelatinosa (lamina II) and also in lamina III. These interneurons then relay the signal to lamina V, where wide dynamic range neurons integrate input from various fibers and send projection signals up the spinothalamic pathway. While C fibers also connect to lamina I, the interneuron-mediated relay to lamina V most consistently involves lamina II and III, making those layers the source of the C-fiber input to lamina V.